Table 2 Difference between the mean number of RTI episodes per year during the follow-up period and the number of episodes of RTI before inclusion in the study stratified according to age classes in the treated (specific extract of duck liver and heart) and untreated groups

1–2 years

-4.22 ± 2.03

-4.77 ± 2.13

-3.17 ± 1.35

0.020

p = 0.361

p = 0.746

p = 0.366

3–5 years

-5.01 ± 2.57

-5.47 ± 2.15

-4.16 ± 3.07

0.007

p = 0.005

p = 0.010

p = 0.138

6–17 years

-4.32 ± 1.30

-4.98 ± 1.24

-3.33 ± 0.54

0.003

p = 0.083

p = 0.063

p = 0.526

18–64 years

-3.83 ± 0.96

-4.44 ± 0.83

-3.28 ± 0.69

0.005

Reference

Reference

Reference

65 years and over

-3.63 ± 1.04

-4.24 ± 0.96

-3.07 ± 0.76

<0.001

p = 0.431

p = 0.775

p = 0.191

Overall p value among age classes

p = 0.010

p = 0.048

p = 0.191

-